The Bingham Canyon Mine is an open-pit mining operation extracting a large porphyry copper deposit southwest of Salt Lake City, Utah, USA, in the Oquirrh Mountains. It is owned by Rio Tinto, an international mining and exploration company headquartered in the United Kingdom. The copper operations at Bingham Canyon Mine are managed through Kennecott Utah Copper Corporation which operates the mine, a concentrator plant, a smelter, and a refinery. The mine has been in production since 1906, and has resulted in the creation of a pit over 0.75 mile (1.2 km) deep, 2.5 miles (4 km) wide, and covering 1,900 acres (7.7 km²). According to Kennecott, it is the world's largest man-made excavation. It was designated a National Historic Landmark in 1966 under the name Bingham Canyon Open Pit Copper Mine.